I. Field of Invention
The present invention relates to an improved, multiple-pin lock cylinder designed to be used as an improved security replacement cylinder in a conventional cylinder type lock, as well as to be the basis for the design of completely new lock mechanisms, incorporating lock-status and intruder-alert information for transmittal to centralized building security systems. This improved lock cylinder is extremely pick-resistant and includes an integral, mechanical, booby-trapped lock-up which functions only when hostile entry is attempted by even the most skilled lock-picking procedures. The several disclosed embodiments of the invention offer practical design options facilitating practical application in spite of the existance of restrictive conventional design and of the highly standardized dimensions that are so well known to manufacturers and locksmiths. As desired, integral sensing or transducing elements may be incorporated as integral components of the cylinders, and connected to communicate information of the lock's status, or to initiate a hostile entry attempt warning into a centralized building security system. The transducing elements may be mechanical, electrical or optical.
II. Description of the Prior Art
The conventional cylinder type lock is well known, widely used and highly regarded, although it has a vulnerability not generally known to the law abiding population. Locksmiths and too many others know that a trained person may "pick" the cylinder of such a lock, and open it without a key. Bent nails, paper clips and hair pins have been used as tools for this purpose. Thus, while such a lock provides adequate protection against unauthorized entry by the average person, it provides relatively little protection against entry by some of those whose access it is most desired to prohibit or control. There is a need therefore, in the art of high security lock design, to provide a relatively simple lock which can exclude the skilled lock picker, but still be ameniable to rekeying and servicing by legitimate mechanics of the locksmithing art, without recourse to the expensive proprietary equipment and supplies required by some contemporary "high-security" cylinder lock systems. Although various locks exist which are more difficult to pick than the conventional multiple-pin tumbler lock, in general those currently offered incorporate in their lock cylinders intricate structures that are expensive to manufacture and/or rely on keys that cannot be duplicated by generally available equipment, causing hardships on the users of such locks when they desire to replace keys or change combinations following loss of keys or changes of personnel or of building occupancy, etc.